Addendum...I just got off chat with a service rep. Return and refund of items for Note 7 bought via Amazon confirmed. Also, original packaging not required but rep indicated they would note that in the account. One cautionary is that if a screen protector is involved, and you still have the phone, remove the screen protector and put it in the package. As I indicated above, I had a package with two protectors; one used on the phone, the other still in the box. It was a 5 minute conversation.
For ease of the chat, have your order number, or numbers, handy..it makes for a faster look-up on their side.
Chat may be found at: https://www.amazon.com/gp/help/customer/contact-us
I selected Prime or Something else, then Amazon Business Question across from the number 2; I didn't have to select anything for number 1. The links for contact options appeared underneath (number 3), in yellow. Just click on chat.